[e2e] e2e principle..where??....

Micah Beck mbeck at cs.utk.edu
Sun Jun 3 16:35:42 PDT 2001

If the end-to-end principle can be paraphrased as "concatenation of
hop-by-hop services are not sufficient to implement an analogous end-to-end
service"  then it would seem that routing is one case where the end hosts
have no way of improving on the job done by the routers.  In fact,
hop-by-hop packet delivery is often very reliable and sometimes even secure,
but the contatentation of hops in routed delivery is not, and it is
necessary to settle for weak datagram delivery in a scalable network.  So we
might say that the end-to-end principle does apply, and gives us an
end-to-end service that is much weaker than the hop-by-hop service.

Perhaps we should think of the end-to-end principle not as forbidding
placing functionality in the network, but rather as predicting the results
of doing so.  Sometimes you have to (or choose to) live with those results.

----- Original Message -----
From: "Jonathan M. Smith" <jms at central.cis.upenn.edu>
To: "Jon Crowcroft" <J.Crowcroft at cs.ucl.ac.uk>; "Lloyd Wood"
<L.Wood at eim.surrey.ac.uk>
Cc: "David P. Reed" <dpreed at reed.com>; "Manish Karir" <karir at wam.umd.edu>;
<end2end-interest at postel.org>; <J.Crowcroft at cs.ucl.ac.uk>
Sent: Sunday, June 03, 2001 7:08 PM
Subject: Re: [e2e] e2e principle..where??....

> Hi Jon,
> Here's a question I once posed in a debate with you at SIGCOMM in Cannes
that I
> have never fully resolved in my own mind. Does the end-to-end argument
> routers as they work today in the Internet? For example, why not source
> as a more "pure" end-to-end strategy? I'm not trying to be antagonistic -
> trying to understand whether the routing control plane (which is network
> embedded in
> the Internet) in fact complies with the e2e principle.
>                                                                          -
> At 10:40 PM 6/3/2001 +0100, Jon Crowcroft wrote:
> >In message
> ><Pine.GSO.4.21.0106032145480.4017-100000 at phaestos.ee.surrey.ac.uk>,
> >Lloyd Wood typed:
> >
> >  >>On Sat, 2 Jun 2001, David P. Reed wrote:
> >  >>
> >  >>> But the idea that something that is done in a
> >  >>> distributed fashion is not against the end-to-end argument, if the
> >  >>> distribution does not place the function into the network layer
> >  >>
> >  >>Is the above an argument against multicast?
> >
> >given many segments are broadcast medium, yo ucould argue it is an
> >argument against unicast (i.e. forward filtering in routers:-)
> >  >>
> >  >>L.
> >  >>
> >  >>all those negatives are making my head hurt.
> >  >>
> >  >><L.Wood at surrey.ac.uk>PGP<http://www.ee.surrey.ac.uk/Personal/L.Wood/>
> >  >>
> >  >>
> >
> >  cheers
> >
> >    jon

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